Removal of heavy metals (Cu 2+ and Cd 2+) from effluent using gamma irradiation, titanium dioxide nanoparticles and methanol

摘要

Heavy metal pollution has become one of the most serious environmental problems. The aim of this study was to achieve an efficient treatment process of effluents containing 1?mM copper (Cu_(2+)) and cadmium (Cd_(2+)) ions using a combination of gamma irradiation, methanol and TiO~(2)nanoparticles under different pH values. The results showed that in acidic conditions, removal of Cu_(2+)and Cd_(2+)ions by physical adsorption was less than 15% and adsorption of Cd_(2+)was more than that of Cu_(2+). In the same condition, the Cu_(2+)removal percentage by irradiation was greater than that of Cd_(2+). In basic solutions, due to precipitation of Cd and Cu hydroxides, it was not possible to carry out adsorption experiments on Cd_(2+)and Cu_(2+)ions removal by TiO~(2)and gamma irradiation. Cu_(2+)and Cd_(2+)ions removal processes under different conditions could be depicted by the first order kinetics model. The combined application of TiO~(2)and methanol enhanced Cu_(2+)and Cd_(2+)ions removal at all pH levels examined. However, using the combination of TiO~(2)and methanol at acidic solutions facilitated completely removal of Cu_(2+)and Cd_(2+)ions. So that, only using 50?kGy irradiation dose with combination of TiO~(2)nanoparticles and methanol led to the removal of 99% of coexisting Cu_(2+)and Cd_(2+)ions from the acidic wastewater.